Debate Over Trump’s Fitness Raises Question of Checks on Nuclear Power

Hillary Clinton has fueled a debate over whether her rival for the presidency, Donald J. Trump, is fit to command America’s atomic forces. “Imagine him in the Oval Office facing a real crisis,” she said in her address at the Democratic convention last week. “A man you can bait with a tweet is not a man we can trust with nuclear weapons.”

This portrayal has become such an issue in the campaign that President Obama was asked about it at a news conference on Thursday, where he echoed Mrs. Clinton’s concerns. Her charge raises a question: Is there any check on a president’s power to launch nuclear arms that could destroy entire cities or nations?

The short answer is no, though history suggests that in practice, there may be ways to slow down or even derail the decision-making process. No one disputes, however, that the president has an awesome authority.

If the United States appeared to be under nuclear assault, the president would have minutes to decide whether the threat was real, and to fire as many as 925 nuclear warheads with a destructive force greater than 17,000 Hiroshima bombs, according to estimates by Hans M. Kristensen, the director of the Nuclear Information Project at the Federation of American Scientists, a private group in Washington.

The commander in chief can also order the first use of nuclear weapons even if the United States is not under nuclear attack.

“There’s no veto once the president has ordered a strike,” said Franklin C. Miller, a nuclear specialist who held White House and Defense Department posts for 31 years before leaving government service in 2005. “The president and only the president has the authority to order the use of nuclear weapons.”

Washington keeps details of the nuclear chain of command and its workings secret. The spokesman for the National Security Council, Ned Price, refused to say whether any other member of the chain of command could stop a presidential order to use nuclear weapons.

Mr. Trump has expressed a deep concern about the power of nuclear weapons in recent interviews, and argued that the nuclear command and control system was so antiquated that some sites still used floppy disks. (He was right, according to an inspector general’s report.) He has not explained under what circumstances he might use nuclear weapons, nor has he ruled out using them first.

Asked in an interview in March whether he would ever use nuclear weapons in a conflict in which the United States was not first attacked with atomic arms, he said he would do so as “an absolute last step.”

“I think it’s the biggest, I personally think it’s the biggest problem the world has, nuclear capability,” he added. He then turned the subject to climate change.

Yet in a March interview on MSNBC, Mr. Trump asked. “Somebody hits us within ISIS, you wouldn’t fight back with a nuke?” He added, “I would never take any of my cards off the table.”

Mrs. Clinton has herself taken hawkish positions in the past. During her bid for the presidential nomination in 2007, she refused to exclude the possible use of nuclear arms against terrorists. Mr. Obama had ruled out such a step against Osama bin Laden, then in hiding.

Mrs. Clinton portrayed herself then as the more experienced candidate. Presidents, she declared, “should be careful at all times in discussing the use and nonuse of nuclear weapons,” adding that she would not address hypothetical questions.

“Presidents since the Cold War have used nuclear deterrents to keep the peace,” she said, “and I don’t believe any president should make blanket statements with the regard to use or nonuse.”

But just a year earlier — before running against Mr. Obama — she seemed to have a different view. Asked about how the Bush administration should try to confront the Iranian nuclear program, she said: “I would certainly take nuclear weapons off the table. This administration has been very willing to talk about using nuclear weapons in a way we haven’t seen since the dawn of a nuclear age. I think that’s a terrible mistake.”

This issue of nuclear arms does not rank at the top of voter concerns, but polls suggest the advantage on this issue is shifting in Mrs. Clinton’s favor. This week, a Fox News poll found that voters had more faith in her ability to handle decisions on nuclear weapons than Mr. Trump, 56 percent to 34 percent. In mid-May, when Fox News first asked the question, the margin in Mrs. Clinton’s favor was half as large.

This is not the first time nuclear weapons have been an issue in a presidential race. In 1964, President Lyndon B. Johnson, in his campaign against Barry Goldwater, broadcast — just once — a television ad that showed a little girl counting flower petals in a field moments before a mushroom cloud filled the screen.

In movies and popular culture, the president is depicted as having a finger on the button. In fact, there is no button, but rather a vast complex of rules and equipment, including careful procedures for the military to authenticate the identity of the commander in chief. The president’s emergency satchel — a black briefcase full of war plans, authentication codes and communication devices — follows him (or her) just about everywhere, carried by an aide trained in the procedures.

The president’s authority over nuclear decision-making challenges the Constitution’s clear declaration that only Congress holds the power to declare war. In practice, the arrival of the nuclear age dismantled the traditional rules by rewriting the timelines of war. It would take 12 minutes or less for weapons fired from submarines to reach Washington, and 30 minutes for warheads from most intercontinental missiles. Bombs dropped by aircraft, if they could pierce the country’s air defenses, would take only hours.

As a result, Congress began delegating the powers of nuclear war-fighting to the president, starting with Harry S. Truman — the only president who has ever ordered a nuclear strike against another nation.

In real life, the lines of authority have blurred — markedly so during the Nixon administration, when there were at least two instances in which top officials tried to slow, or undermine, the president’s nuclear authority.

The first came in October 1969, when the president ordered Melvin R. Laird, his secretary of defense, to put American nuclear forces on high alert to scare Moscow into thinking the United States might use nuclear arms against the North Vietnamese.

Scott D. Sagan, a nuclear expert at Stanford University and the author of “The Limits of Safety,” a study of nuclear accidents, said Mr. Laird tried to ignore the order by giving excuses about exercises and readiness, hoping that the president who sometimes embraced the “madman theory” — let the world think that you are willing to use a weapon — would forget about his order.

But Nixon persisted. Dr. Sagan reports that during the operation, code-named Giant Lance, one of the B-52 bombers carrying thermonuclear arms came dangerously close to having an accident.

Then, in 1974, in the last days of the Watergate scandal, Mr. Nixon was drinking heavily and his aides saw what they feared was a growing emotional instability. His new secretary of defense, James R. Schlesinger, himself a hawkish Cold Warrior, instructed the military to divert any emergency orders — especially one involving nuclear weapons — to him or the secretary of state, Henry A. Kissinger.

It was a completely extralegal order, perhaps mutinous. But no one questioned it.

“Although Schlesinger’s order raised questions about who was actually in command,” Eric Schlosser writes in “Command and Control,” a 2013 book, “it seemed like a good idea at the time.”

Experts agree that the real nightmare of nuclear command centers not on launching attacks, but responding to them. In a recent memoir, William J. Perry, secretary of defense to President Bill Clinton, called it “the immense peril we face when in mere minutes our leaders must make decisions affecting the whole planet.”

In 1980, Zbigniew Brzezinski, the national security adviser to President Jimmy Carter, was awakened by news of an impending nuclear attack that was lighting up the screens at the military’s early-warning command centers.

He asked the military officer who called him for more information and confirmation. The next call said that the attack involved not just submarines but thousands of warheads fired from land-based missiles.

As Mr. Brzezinski prepared to phone the president, the officer called again to say it was all a mistake — a computer had generated a false alarm.

The episode poses the ultimate question for a new administration, a set of judgments that the president, the secretary of defense and the national military command often rehearse in secret, especially at the beginning of a presidency. Because all warning systems are subject to error, the president has to decide, often in minutes, whether to “launch on warning,” to “launch on attack” or — perhaps the hardest decision of all — to absorb a first nuclear attack rather than risk launching on false information.

In the case of Mr. Trump, some members of the Clinton campaign have raised a different fear: that the man who regards himself as America’s best negotiator may try to use the threat of employing nuclear weapons as a bargaining chip.

This week, Joe Scarborough on MSNBC’s “Morning Joe” said that Mr. Trump had asked an unnamed adviser what the utility of nuclear weapons was if no one was willing to use them. The Trump campaign denies that.

Some who have discussed nuclear strategy with Mr. Trump — often in the context of the Iran deal signed last summer — said that he had never expressed a desire to use such weapons, but lacked knowledge of the history of deterrence, and that the negotiator in him seemed interested in the question of whether the United States should ever threaten to use its arsenal.

That threat alone, of course, could have tremendous consequences. It could give another country a motive to invest in a nuclear arsenal. Or if — like North Korea or Pakistan — it already possesses nuclear weapons, the threat could prompt the country to use them pre-emptively.

“Some people have an ability to negotiate,” he told her. “It’s an art you’re basically born with. You either have it or you don’t.” He assured her he could learn about missiles quickly. “It would take an hour and a half to learn everything there is to learn about missiles. … I think I know most of it anyway,” he said.

Decades of arms reductions, and President Obama’s oft-stated goal of making nuclear weapons less central to American defenses, have put only a modest dent in Washington’s ability to initiate the unthinkable.

Some scholars (and Wikipedia entries) insist that a system of checks and balances puts the secretary of defense in the decision loop. But Bruce G. Blair, a research scholar at Princeton University who as an Air Force officer would have launched a nuclear missile if an order had come from the president, said that rule applied in the silos but not at the top of the command chain.

“There’s nothing the secretary of defense can do,” Dr. Blair, who wrote a book on nuclear command and control, said in an interview. “He has no authority to refuse or disobey that order.”

Mr. Sagan, the Stanford expert, agreed, but noted that there were other ways for the secretary of defense to slow things down. “I think we’d be in uncharted waters if a president ordered the use of nuclear weapons and the secretary of defense refused to concur,” he said. “This has never happened.” No one, he added, could predict what would ensue if the nation’s top defense official tried to declare that the president was unfit to issue such an order.

“In some scenarios,” Mr. Sagan added, “such as an unprovoked nuclear attack by a president in peacetime, a constitutional crisis would be more likely than a prompt following of rules regarding succession and command authority.”